# Sanitary Sewer: Building Code Definition

> How the IRC 2009 define sanitary sewer, where the wording differs, and which chapters depend on the term.

- Canonical: https://harth.build/resources/glossary/sanitary-sewer/
- Last updated: 2026-09-07
- Data source: Definitions quoted from the 2009 International Codes as transcribed in this site's building-codes collection, with the source chapter linked for each quotation. Usage counts are computed over the chapters hosted here, one copy per code. The [ICC code library](https://codes.iccsafe.org/codes) publishes the current model text and the [ICC adoption maps](https://www.iccsafe.org/advocacy/code-adoption-maps/) show which edition a jurisdiction has adopted; those sources control.

## Key facts

| Fact | Value |
| --- | --- |
| Defined in | IRC 2009 (2009 editions transcribed in this corpus) |
| Primary source | IRC 2009 Definitions (model text, not a jurisdiction's adopted text) |
| Chapters using the term | 3 (counted across the codes hosted here) |
| Wording identical across codes | Single code (compare before citing one code's wording under another) |

## Direct answer

Sanitary sewer is a defined term in the International Residential Code (IRC) 2009, in Definitions. The code's own words are: “A sewer that carries sewage and excludes storm, surface and groundwater.” No other I-Code in this corpus defines it, so the IRC 2009 definition is the one to work from. The term is used in 3 chapters of this corpus, most often in Definitions (IPC 2009), Building Planning (IRC 2009), Definitions (IRC 2009). These pages transcribe the 2009 model text; verify the definition against the edition and amendments your authority having jurisdiction has adopted. Record the jurisdiction, the adopted edition, the application date and any local amendment that rewrites the definition before you use it on a live project, because a term redefined by amendment changes every requirement that depends on it.

*Content and cited inputs reviewed by [Scott Barrington](https://nz.linkedin.com/in/barrington), Harth founder and architectural technology specialist · Published 2026-09-07 · Updated 2026-09-07.*

## What does this term mean?

**Sanitary Sewer** — IRC 2009, Definitions:

> A sewer that carries sewage and excludes storm, surface and groundwater.

![Labeled code-term definition diagram: Sanitary Sewer: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/sanitary-sewer/diagram-1344.webp)

*How the IRC 2009 define sanitary sewer, where the wording differs, and which chapters depend on the term.*

## What must be verified before using this guidance?

**Sanitary Sewer** is defined once in this corpus, in the [Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/definitions.md) chapter of the International Residential Code (IRC) 2009:

> A sewer that carries sewage and excludes storm, surface and groundwater.

## Where sanitary sewer is used in the code

The term appears in 3 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.

| Chapter | Code | Mentions |
| --- | --- | --- |
| [Definitions](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/definitions.md) | IPC 2009 | 2 |
| [Building Planning](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/building-planning.md) | IRC 2009 | 1 |
| [Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/definitions.md) | IRC 2009 | 1 |

### The term in use

How the code actually writes about sanitary sewer, quoted from the 2009 text hosted here:

> All plumbing fixtures shall be connected to a sanitary sewer or to an approvedprivate sewage disposal system.

— [IRC 2009 §R306.3](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/building-planning.md)


## The terms sanitary sewer is built out of

The definition above leans on 1 other defined term. Each carries its own code definition, and a local amendment to any of them changes what sanitary sewer covers:

- **[Sewage](https://harth.build/resources/glossary/sewage.md)** — IRC 2009: Any liquid waste containing animal matter, vegetable matter or other impurity in suspension or solution.

## Sanitary Sewer: what to open, and in what order

Every row is a document this term depends on. The [ICC code library](https://codes.iccsafe.org/codes) and the [ICC adoption maps](https://www.iccsafe.org/advocacy/code-adoption-maps/) cover the middle rows.

| Check | Where | Confirmed |
| --- | --- | --- |
| Read the definition in the adopted IRC | Definitions | |
| Re-check the requirement that uses it | Definitions (IPC 2009) | |
| Re-check the requirement that uses it | Building Planning (IRC 2009) | |
| Re-check the requirement that uses it | Definitions (IRC 2009) | |
| Confirm the dependent definition | Sewage | |
| Local amendment to any of the above | Jurisdiction's amendment list | |

**A research aid, not a code determination.** The authority having jurisdiction decides which edition and which amendments apply.

## Where can you explore related guidance?

- [Explore all glossary guidance](https://harth.build/resources/glossary.md)
- [Sewage: Building Code Definition](https://harth.build/resources/glossary/sewage.md)
- [Building: Building Code Definition](https://harth.build/resources/glossary/building.md)
- [Construction Documents: Building Code Definition](https://harth.build/resources/glossary/construction-documents.md)
- [Registered Design Professional: Building Code Definition](https://harth.build/resources/glossary/registered-design-professional.md)

## Sources and method

Definitions quoted from the 2009 International Codes as transcribed in this site's building-codes collection, with the source chapter linked for each quotation. Usage counts are computed over the chapters hosted here, one copy per code. The [ICC code library](https://codes.iccsafe.org/codes) publishes the current model text and the [ICC adoption maps](https://www.iccsafe.org/advocacy/code-adoption-maps/) show which edition a jurisdiction has adopted; those sources control.

### Source links

- [codes.iccsafe.org](https://codes.iccsafe.org/codes)

- [iccsafe.org](https://www.iccsafe.org/advocacy/code-adoption-maps/)

## Frequently asked questions

### What is the code definition of sanitary sewer?

The International Residential Code (IRC) 2009 defines it in Definitions as: “A sewer that carries sewage and excludes storm, surface and groundwater.” The 2009 model text is reproduced here; the definition that binds your project is the one in the edition your jurisdiction has adopted, as amended locally.

### Which parts of the code depend on sanitary sewer?

In this corpus the term is used across 3 chapters, led by Definitions in the IPC 2009. Those are the sections whose scope moves if the definition is amended locally, so read them together with Chapter 2 rather than on their own.

### What is considered a sanitary sewer?

In the 2009 I-Codes hosted here it is a defined term rather than a description. The IRC 2009 states, in Definitions: “A sewer that carries sewage and excludes storm, surface and groundwater.” It is defined in IRC 2009. Because it is a defined term, whatever the adopted edition says it means is what every section using it means — so check Chapter 2 of that edition and any local amendment before relying on this wording.

### What is the minimum slope for a sanitary sewer?

In the 2009 I-Codes hosted here it is a defined term rather than a description. The IRC 2009 states, in Definitions: “A sewer that carries sewage and excludes storm, surface and groundwater.” It is defined in IRC 2009. It is not the same as Slope, which the IRC 2009 defines separately as “The fall (pitch) of a line of pipe in reference to a horizontal plane. In drainage, the slope is expressed as the fall in units vertical per units horizontal (percent) for a length of pipe.” Because it is a defined term, whatever the adopted edition says it means is what every section using it means — so check Chapter 2 of that edition and any local amendment before relying on this wording.

### What is the IRC plumbing code?

Plumbing is a separate defined term. The IRC 2009 defines it as: “For the purpose of this code, plumbing refers to those installations, repairs, maintenance and alterations regulated by Chapters 25 through 33.” That is not the same as sanitary sewer, which the IRC 2009 defines as “A sewer that carries sewage and excludes storm, surface and groundwater.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

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